In his unique invention the Ocean Arrow, an "underwater helicopter," Tom Swift Jr. embarks on a precarious search for a lost rocket from space.

The rocket, containing evidence of living things on another planet, was directed to Swift Enterprises for scientific study. But its course was mysteriously changed while the rocket was hurtling toward earth--and its landing site is unknown!

Tom suspects that the rocket lies underwater, somewhere off the coast of South America, Accompanied by his friends, Bud Barclay and Chow Winkler, and two expert oceanographers, the young inventor sets out in his diving seacopter to locate the rocket.

But a group of unethical scientists have uncovered a clue to this valuable treasure from space. In their own undersea craft, they try to thwart Tom in his attempt to claim the rocket which rightfully belongs to Swift Enterprises.

Unexpected dangers confront the Swift expedition every mile of the seraph for the scientific prize. When the Ocean Arrow is trapped in a crushing, underwater landslide, Tom and his companions nearly lose their lives. How they overcome subocean hazards, as well as their cunning enemies, makes one of the most exciting stories to date in the TOM SWIFT JR. series.

The summary below was written by Graeme Woods. Thanks again for volunteering!

Major Inventions

The most important invention in this book is the diving seacopter. This is how Tom introduces his latest invention to Bud:

"You mean an underwater airplane?"

"No. A flying submarine."

"Cut the kidding," Bud retorted.

"Itís the truth," Tom continued. "Itíll even crawl around if necessary on tractor treads."

"No fooling! What do you call it?"

"A diving seacopter."

Another minor invention that is mentioned in passing is the Eye-Spy camera. This is how Tom describes it:

"Takes motion pictures and records sounds through walls or solid objects," Tom replied. "Five seconds later it projects the result on the screen and player. Actually itís an improvement on Dadís old television detector."

The book does not detail the Eye-Spy cameraís principles of operation, and I canít guess how it would work.

How does the Diving Seacopter work?

The seacopter is essentially a nuclear powered saucer shaped underwater helicopter that can also fly in the air. It comprises a central rotor section with variable pitch blades that provide lift in the air. The pitch of the blades is reversed for submerging and the blades turn slower due to the higher density of water compared to air. The nuclear reactors also power jets that provide steering.

This is how Tom explains the benefits of this approach:

"The big advantage of this kind of submersion," Tom continued, "is that these blades eliminate the need for ballast tanks. With the rotors, the seacopter can easily stay at any level beneath the surface the navigator chooses, merely by adjusting the blade pitch."

The seacopter can surface without power, as it is naturally buoyant. It also has tractor treads for crawling around the bottom of the ocean.

The diving seacopter is nuclear powered as explained by Tom:

"Each compartment has a miniature atomic reactor which manufactures the superheated steam," Tom explained. "This steam is then released out the jet pipes underneath the compartment. When the seacopter is all assembled, steam for the jets will be channeled from the excess used to drive the rotor blades."

I would expect that when the seacopter is flying, the atomic reactors are used to superheat air to power the steering jets and the rotor, similar to the Sky Queen.

The book explains the layout of the seacopter as follows:

He noticed that the seacopter was divided into three sections: a cabin at either end, called Compartments A and B ñ each of which would accommodate 3 people ñ and the center section containing the rotor blades. This section was open top and bottom to allow the water in. It had narrow corridors on either side of it for passengers to walk from one compartment to the other.

Compartments A and B (later dubbed Subro and Airmo) can separate and operate independently if required and Tom is forced to separate the units when Subro is damaged in an underwater landslide.

When this happened, I was surprised that the Airmo nuclear reactor did not continue to provide power, since each section is independent. Presumably the reactor must have been damaged in the accident. Although the solar battery was damaged by water, preventing the use of the radio, Tom was able to use the tractor treads to ride up on the beach. Where did the power for this come from?

Would the Diving Seacopter work?

I believe that the seacopter could work. The saucer shape is particularly interesting as this allows motion in any direction through both air and water. The seacopter is very similar to Cousteau's Diving Saucer (although the Diving Saucer is tiny compared to the 40 foot seacopter) as this craft also has positive buoyancy and uses jet propulsion.

However, I think that there would be some significant practical issues to overcome.

Firstly, the atomic reactors would need to be light enough to allow the seacopter to fly, even after providing heavy shielding to protect the crew against radiation. When Tom designed the Flying Lab, he used Tomasite to shield against radiation without adding excessive weight, so I imagine he has used this material in the seacopter.

Also, the seacopter could not release any radioactive materials into the environment and would need to operate in corrosive seawater. This means that it could not run water or air directly through the core of the reactor, but would need a heat exchanger to transfer the heat from the reactor to water or air. This tends to add weight.

Experiments into using atomic power for aircraft were conducted in the 1950ís and early 1960ís but were abandoned after enormous technical problems and safety issues. I believe that it is very unlikely that we will see fission-powered aircraft of any description in the near future because of the greater public awareness of the dangers of exposure to radioactivity.

Secondly, the rotor unit and blades would need to work properly in both air and water (water is approximately 800 times denser than air). I think that this would present a significant design challenge. Tom has difficulties with the rotor design, but this is corrected by developing a new alloy and changing the design of the blades.

What impact would the Diving Seacopter have on our lives?

I think that the concept of a flying submarine would be useful to two major groups; the military and scientists. A craft that could operate in both air and water would be a powerful weapon for the worldís navies. It would also help oceanographers explore under the ocean as a seacopter could travel under its own power to the exploration site without the need for support vessels and resultant delays.

The positive buoyancy would add to safety. If there was a problem, the seacopter would simply float to the surface.

Outside of these specialised applications, I think that the nuclear technologies in the seacopter (light weight shielding, miniature reactors and heat exchangers) would be enormously beneficial if feasible (and the problem of radioactivity could be overcome).

If nuclear powered aircraft were safe, flight duration would no longer be limited by available fuel. Fuel costs are a significant cost in running any aircraft. However, as mentioned above, I think that the safety issues are insurmountable ñ no-one wants the risk of nuclear materials being spread a reactor rupturing in an aircraft crash or being exposed to radiation during flight.